Impulsivity appears to play an important role in suicidal behaviors and drug abuse, which are two psychiatric problems that may interact with one another. Interpretation of the literature on impulsivity in these behaviors may be complicated by the variety of measurement techniques for the assessment of impulsivity. There are three general types of impulsivity assessment: self-report, biological, and laboratory behavioral. Because laboratory behavioral measures both meet an operational definition of impulsivity and are sensitive to state-dependent changes in impulsivity, this paper presents data that focuses on laboratory behavioral performance among samples emitting suicidal behaviors or substance abuse. To better account for influence of impulsivity in these psychiatric disturbances, no single source of measurement should be used without the consideration of other types of instruments.